glibc/sysdeps/unix/sysv/linux/sparc/sparc32/sigaction.c
Nick Alcock 2e6c45c59b Do not stack-protect sigreturn stubs [BZ #7065]
These are called from the kernel with the stack at a carefully-
chosen location so that the stack frame can be restored: they must not
move the stack pointer lest garbage be restored into the registers.

We explicitly inhibit protection for SPARC and for signal/sigreturn.c:
other arches either define their sigreturn stubs in .S files, or (i386,
x86_64, mips) use macros expanding to top-level asm blocks and explicit
labels in the text section to mock up a "function" without telling the
compiler that one is there at all.
2016-12-26 10:11:06 +01:00

89 lines
2.4 KiB
C

/* POSIX.1 sigaction call for Linux/SPARC.
Copyright (C) 1997-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Miguel de Icaza <miguel@nuclecu.unam.mx>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <string.h>
#include <syscall.h>
#include <sys/signal.h>
#include <errno.h>
#include <kernel_sigaction.h>
#include <sysdep.h>
static void __rt_sigreturn_stub (void);
static void __sigreturn_stub (void);
int
__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
{
struct kernel_sigaction kact, koact;
unsigned long stub = 0;
int ret;
if (act)
{
kact.k_sa_handler = act->sa_handler;
memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t));
if (((kact.sa_flags = act->sa_flags) & SA_SIGINFO) != 0)
stub = (unsigned long) &__rt_sigreturn_stub;
else
stub = (unsigned long) &__sigreturn_stub;
stub -= 8;
kact.sa_restorer = NULL;
}
/* XXX The size argument hopefully will have to be changed to the
real size of the user-level sigset_t. */
ret = INLINE_SYSCALL (rt_sigaction, 5, sig, act ? &kact : 0,
oact ? &koact : 0, stub, _NSIG / 8);
if (oact && ret >= 0)
{
oact->sa_handler = koact.k_sa_handler;
memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t));
oact->sa_flags = koact.sa_flags;
oact->sa_restorer = koact.sa_restorer;
}
return ret;
}
libc_hidden_def (__libc_sigaction)
#include <nptl/sigaction.c>
static
inhibit_stack_protector
void
__rt_sigreturn_stub (void)
{
__asm__ ("mov %0, %%g1\n\t"
"ta 0x10\n\t"
: /* no outputs */
: "i" (__NR_rt_sigreturn));
}
static
inhibit_stack_protector
void
__sigreturn_stub (void)
{
__asm__ ("mov %0, %%g1\n\t"
"ta 0x10\n\t"
: /* no outputs */
: "i" (__NR_sigreturn));
}